Heating, ventilation, and air conditioning (HVAC) systems can be used to regulate an environment within an enclosure. Typically, a circulating fan is used to pull air from the enclosure into the HVAC system through ducts and to push the air back into the enclosure through additional ducts after conditioning the air (e.g. heating or cooling the air). For example, a gas furnace, such as a residential gas furnace, is used in a heating system to heat the air.
Existing heating systems use two heating stages that are sized for peak periods of the year where maximum heat is required. For example, existing heating systems are typically sized to produce either 100% or 75% of their maximum heat output. During operation, these existing systems are cycled frequently and create high discharge air temperatures that may cause heating related issues such as stratification within a room. It is desirable to provide a heating system that allows for better discharge air temperature control.